Update | Intel 14th-gen stability BIOS update obliterates multicore performance with 23% loss in some benchmarks ^↺

Update: The performance degradation seen in the testing referenced throughout this article appear to be isolated to Asus motherboards, specifically. Testing by JayzTwoCents on YouTube (watch below), using an MSI motherboard and a variety of Intel 14th-gen CPUs, revealed negligible performance changes after installing the 0x129 microcode update. While the performance degradations on Asus motherboards may not have been caused by Intel's microcode, they may have been a side effect of trying to push out a BIOS update quickly to mitigate further CPU damage. Thanks to our astute readers for pointing this out. 

Intel's recent 13th- and 14th-gen CPU instability and degradation issues came to a head this week, when Intel more or less admitted fault and promised a microcode update that it claimed would not affect performance. However, after installing the update on an Asus Maximum Z790 motherboard and testing it with an Intel Core i9-14900K, PC Guide found quite the opposite to be true. 

It's unclear whether the fault lies with Intel's 0x129 microcode update or something else in the Asus beta BIOS, but multicore performance seems to have been significantly impacted by the BIOS update. PC Guide tested two different heavily multithreaded benchmarks immediately before and immediately after the BIOS update and found consistent performance degradation of 22–23% in each. 

In Cinebench, the unlocked Core i9's score dropped a whopping 9,123 points from 39,783 to 30,660 points — or 22.9%. The publication's Blender render test also saw significant performance losses of 22%. The consistency of the performance loss in the multicore benchmarks — one synthetic and the other more realistic — indicates there is some significance to the results. 

Fortunately, there was no apparent effect to gaming performance, with the CPU scoring identical FPS in Counter Strike 2, Cyberpunk 2077, and Days Gone before and after the update. 

Interestingly, during both the Blender and Cinebench multicore tests, per-core CPU voltage was slightly higher after the update, meanwhile per-core CPU clocks and CPU temperatures were significantly lower after the update. Looking at the average CPU temperatures and abnormally low clock speeds during the testing, it's reasonable to conclude that something about Intel's Thermal Velocity Boost wasn't working properly during the testing. 

It remains to be seen how things play out as Intel and its board partners continue to address the CPU degradation fiasco, but if this microcode update is any indication, Intel CPU owners might want to strap in for some performance degradation. 

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